linux-kernel - [PATCH] usb: dwc2: host: use msleep() for long delays

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Message-Id: <1484236443-32731-1-git-send-email-hofrat@osadl.org>
Date:   Thu, 12 Jan 2017 16:54:03 +0100
From:   Nicholas Mc Guire <hofrat@...dl.org>
To:     John Youn <johnyoun@...opsys.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Nicholas Mc Guire <hofrat@...dl.org>
Subject: [PATCH] usb: dwc2: host: use msleep() for long delays

ulseep_range() uses hrtimers and provides no advantage over msleep()
for larger delays. Fix up the 20+ ms delays here passing the adjusted "min"
value to msleep(). This helps reduce the load on the hrtimer subsystem.

Signed-off-by: Nicholas Mc Guire <hofrat@...dl.org>
---

Patch was compile tested with: x86_64_defconfig + CONFIG_USB_DWC2
(1 sparse and 6 coccinelle warning - preparing separate patches for that)

Patch is against 4.10-rc3 (localversion-next is next-20170112)

 drivers/usb/dwc2/hcd.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 911c3b3..37ee72d 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -2150,7 +2150,7 @@ static int dwc2_hcd_endpoint_disable(struct dwc2_hsotg *hsotg,
 		}
 
 		spin_unlock_irqrestore(&hsotg->lock, flags);
-		usleep_range(20000, 40000);
+		msleep(20);
 		spin_lock_irqsave(&hsotg->lock, flags);
 		qh = ep->hcpriv;
 		if (!qh) {
@@ -3240,7 +3240,7 @@ static void dwc2_conn_id_status_change(struct work_struct *work)
 				 "Waiting for Peripheral Mode, Mode=%s\n",
 				 dwc2_is_host_mode(hsotg) ? "Host" :
 				 "Peripheral");
-			usleep_range(20000, 40000);
+			msleep(20);
 			if (++count > 250)
 				break;
 		}
@@ -3261,7 +3261,7 @@ static void dwc2_conn_id_status_change(struct work_struct *work)
 			dev_info(hsotg->dev, "Waiting for Host Mode, Mode=%s\n",
 				 dwc2_is_host_mode(hsotg) ?
 				 "Host" : "Peripheral");
-			usleep_range(20000, 40000);
+			msleep(20);
 			if (++count > 250)
 				break;
 		}
@@ -3354,7 +3354,7 @@ static void dwc2_port_suspend(struct dwc2_hsotg *hsotg, u16 windex)
 
 		spin_unlock_irqrestore(&hsotg->lock, flags);
 
-		usleep_range(200000, 250000);
+		msleep(200);
 	} else {
 		spin_unlock_irqrestore(&hsotg->lock, flags);
 	}
@@ -3378,7 +3378,7 @@ static void dwc2_port_resume(struct dwc2_hsotg *hsotg)
 		pcgctl &= ~PCGCTL_STOPPCLK;
 		dwc2_writel(pcgctl, hsotg->regs + PCGCTL);
 		spin_unlock_irqrestore(&hsotg->lock, flags);
-		usleep_range(20000, 40000);
+		msleep(20);
 		spin_lock_irqsave(&hsotg->lock, flags);
 	}
 
@@ -3691,7 +3691,7 @@ static int dwc2_hcd_hub_control(struct dwc2_hsotg *hsotg, u16 typereq,
 			}
 
 			/* Clear reset bit in 10ms (FS/LS) or 50ms (HS) */
-			usleep_range(50000, 70000);
+			msleep(50);
 			hprt0 &= ~HPRT0_RST;
 			dwc2_writel(hprt0, hsotg->regs + HPRT0);
 			hsotg->lx_state = DWC2_L0; /* Now back to On state */
-- 
2.1.4